Ubuntu audio issues

Having a few strange audio issues with Ubuntu 18.10

On starting the pc, whenever audio is played it only plays from the left channel. If I go into the sound settings, the panning slider is exactly in the middle where it should be. As soon as it is adjusted audio plays from both speakers. No idea why its doing that.

Also, replay gain is all over the place.

I just switched from Windows where I was using Musicbee. Its built in replay gain worked perfectly. In linux, its only reducing the volume of ‘louder’ tracks, so anything that is quiet stays quiet. Musicbee didnt do that, it set everything to the same level. Not sure how to remedy this.

Software used - Rhythmbox (using the replaygain that comes with it, not an external plugin)
Hardware - Asus Xonar Essence STX